1. Field of the Invention
The invention relates generally to security systems, and more particularly, the invention relates to a system for automatically verifying that a newborn infant is correctly matched with its parents and for ensuring the security of the newborn infant within a hospital.
2. Description of the Related Technology
The abduction of infants from hospital maternity wards happens with alarming frequency. The incorrect matching of newborn infants and parents also occurs much too often. That either of these events occur at all is unacceptable, particularly if it is your baby.
To ensure that mother and infant are correctly matched together, hospitals presently use a system of coded badges that are secured to each of the mother and the infant. Typically, a multi-digit code is printed on a wristband which is secured to the mother, and a wrist and/or ankle band bearing a matching multi-digit code is secured to the infant. The mother""s badge is secured prior to delivery, and the infant""s badges are secured as soon as practical after delivery while both the mother and infant remain in the delivery room. When mother and infant are later united, for example when the infant is brought from the nursery to the mother""s recovery room, a hospital staff member is instructed to verify the numbers match to ensure the correct infant is united with the correct mother. Mothers are also encouraged to check that the numbers match. As an alternative to the infant wrist or ankle band, it has been proposed to imprint the code on an umbilical clamp and to provide the mother with a wristband again bearing a matching code. It is suggested that the umbilical clamp system ensures that the coded band does not inadvertently detach itself from the infant. With either wrist/ankle bands or umbilical clamps, the system requires human intervention to function correctly, and errors in matching mother and infant can still occur if the hospital staff or the mother fail to check or are careless in checking that the coded numbers match.
In spite of the care exercised by the hospital staff, the mismatching of mothers and infants continues to happen. The problem lies with the fact that there is no backup for the possibility of human error. For example, if an error is made when the infant is brought to its mother before discharge, it is possible that the mother may leave the hospital with the wrong infant before error is detected. Furthermore, there is no positive feedback to either the mother or the hospital staff person making the matching verification that they have in fact correctly observed and matched the multi-digit numbers.
Infant abduction from hospital maternity wards it is sad to say is a growing problem. To combat such abductions, it has been proposed to provide radio frequency transmitters within the wrist or ankle band secured to the infant. Alternatively, magnetic strips or similar remotely excited circuits or materials may be placed within the wrist or ankle band. In still other proposed arrangements, the transmission device is secured within an umbilical clamp. Radio frequency receivers are positioned near exits from either the maternity ward and/or the hospital, and an alarm is sounded should an infant, wearing a transmission capable badge, be brought into proximity with the receiver.
To be effective, the radio frequency signals generated in the wrist and/or ankle bands have to be transmitted with sufficient strength to ensure that the infant is detected within the maternity ward and/or to ensure detection at the exit. However, transmitting the signals with increased power, i.e., such that they have sufficient signal strength to ensure detection, severely limits their usefulness for precisely locating the infant. This is because radio frequency signals will penetrate and pass through walls, floors, ceilings, and various other substantially non-conductive boundaries. So, while a radio receiver may be located in a room separate from where the infant is actually located, it may still be very much capable of receiving the signal from the infant""s badge. In fact, the infant may be located in different rooms, on different floors, or outside of the hospital entirely. Therefore, it is impractical to use the radio frequency signals to locate the infant within the hospital. It has been suggested that relative signal strength indications (RSSI) along with triangulation may be used to better identify the location of a RF transmitter in a hospital application. However, RSSI value is greatly influenced by a number of factors including multi-path, Rayleigh fading, interference, and the like, limiting its effectiveness when used alone for identifying the precise location of the transmitter.
RF systems utilizing magnetic strips or other remotely excited circuits rely on detection of a resonant signal generated within the badge in response to an excitation signal to detect the presence of the badge near the reader. Unfortunately, these systems require the badge to be placed in close proximity and with proper orientation to the reader to be effectively energized and read. These systems fail as the badge can not always be in close proximity to a reader during matching of infant and mother. As precise location information is required to ensure proper matching of infant and mother, these RF systems are not viable for providing a matching function.
Infrared (IR) transmitters and receivers are commonly used in the hospital environment to locate equipment and personnel. The advantage of using IR signals for providing location information is that the IR signals do not penetrate walls, floors, ceilings or other substantially opaque boundaries. Thus, by locating an IR receiver in each room of the hospital, it is possible to know precisely which room within the hospital the transmitting device is located. Infrared signals, however, are easily blocked. If disposed within a wristband or ankle band secured to an infant, and certainly with an umbilical clamp, it is likely that the signals will be blocked by clothing or blankets in which the infant is wrapped. Thus, IR technology, while offering the promise of providing precise location, does not provide the assured detection required for security purposes.
Thus, there is a need for a system which offers the capability to precisely locate both mother and infant within the hospital and to provide an indication that mother and infant are correctly matched. Additionally, the system must further have the capability to detect the presence of the infant within the hospital and to detect the attempted unauthorized removal of the infant from the maternity ward and/or the hospital.
A system in accordance with the preferred embodiments of the invention 1) ensures mother and infant are correctly matched post-partum, 2) continuously monitors the presence of the infant within the hospital and particularly within the hospital maternity ward, and 3) detects and signals the unauthorized removal of the infant from either the hospital maternity ward and/or the hospital entirely.
In one aspect of the invention, a dual-mode infrared/radio frequency (IR/RF) transmitter is secured within a wristband worn by the mother and within an ankle and/or wristband worn by the infant. In a matching mode of operation, IR signals are received by infrared receivers located at various locations in and around the hospital to precisely and automatically determine by proximity that mother and infant are correctly united. In a presence detecting mode, RF signals from the infant""s badge are detected by RF receivers located throughout the maternity ward of the hospital or throughout the hospital generally. In a security mode, RF receivers located proximate exits of either of the maternity ward and/or the hospital detect RF signals from the ankle and provide a signal to generate an alarm.
In another aspect of the invention, an IR receiver and an RF receiver may be integrated into a single unit.
Another feature of the invention provides for an audio and/or visual signal for providing an indication mother and infant are correctly matched.
In still another aspect of the invention, each of the mother""s wristband and the infant""s badge are capable providing an indication that mother and infant are correctly matched.
In yet another aspect of the invention, each of the IR signals and the radio frequency signals have a common modulation and are distinguished to the receiver by a header message.
In another aspect of the invention, the mother""s wristband and/or the infant""s ankle band include a motion sensor and capability of modifying its transmitted signal should it fail to detect motion associated with being secured to the mother or infant.
Still an additional aspect of the invention provides for each of the IR and RF signals to be sent in short bursts randomly distributed within a larger window of time.
An additional feature of the invention permits simultaneous use of numerous ankle bands within a single nursery without mutually interfering.
Another aspect of the invention provides packaged, ready to use dual-mode wristbands and/or ankle bands in sets to be matched upon initialization within the birthing room.